Factual error: The Big A store sells beer and wine. In Rhode Island, it is not allowed for convenience stores to sell alcohol.
Continuity mistake: When the bus is driving to the museum the camera goes to Lloyd and Harry. In the window you see a car passing. When the movie shows an overhead shot of the road, there is no car in front or to the side of the bus.
Continuity mistake: In the scene when "There's shit everywhere" in the bathroom, it is taking place at night. But in the shots of Jessica's dad in the bathroom doorway, there is sunlight coming through the window across the hall.
Continuity mistake: When the teacher asks her "special needs class" if they have any ideas for a float, the camera switches between people and conversations and every single time this happens the Chinese exchange student changes position (resting on her elbow, arms out stretched, hands together etc...)
Continuity mistake: Louis has a black eye from Lloyd hitting him while in his pirate costume, as Lloyd finds out when he is wearing the "polar wear". Then, in the special needs class that same day, we see Louis without the black eye.
Continuity mistake: When Harry is drinking his Slushy fast, some drips on his neck and leaves a stain. Then, when Jessica comes, the stain is gone.
Continuity mistake: The chip of Lloyd's tooth on Harry's forehead is bigger than the piece missing.
Continuity mistake: When Harry and Lloyd fall through the ceiling, they start to walk down the hall, away from the ceiling debris, for about 20 seconds, but when the camera angle changes to their backs, they're next to the debris again.
Continuity mistake: When Harry and Lloyd are in Big A goofing off, when Lloyd says "invisibility shield", the store clerk is seen moving and bending over a bit to put something down on the shelf, but in the next shot, he's back in the upright position.
Revealing mistake: When Harry and Lloyd collide, Lloyd's tooth goes into Harry's forehead. When he pulls it out, he doesn't even bleed, and it leaves a little mark. Also, the little mark from the tooth is gone by the next scene.
Factual error: In the scene where the principal is in the car asking about the chest. They pass by a house with a 1990's Chevrolet Suburban.
Continuity mistake: After Lloyd breaks the window with his message via a large brick, the glass on the left side of the window sill keeps shifting back and forth 90 degrees from shot to shot.
Continuity mistake: When the special needs class is debating a float, look at the chalkboard in the background. The word 'float' is underlined, then the next time you see it, it isn't underlined. This occurs a number of times throughout the scene.
Answer: I can't find any credited source saying that Kyle Gass was in this movie.
T Poston